With this, Tata Power's total generation capacity stood at 7,699 MW, making it the largest private power producer in the country, the company said in a release.

The first 800 MW unit at the Mundra power plant was commissioned in March, unit II in July and unit III in October 2012.

With the synchronisation of the fourth unit, the total thermal power generation capacity of Tata Power now stands at 6,847 MW, and that through hydropower, wind and solar 852 MW.

"The synchronisation of Unit 4 of the Mundra ultra mega power project is a significant milestone given the critical power shortage situation in the country," said Anil Sardana, managing director, Tata Power.

CGPL Thursday discontinued supply to the distributing companies of Rajasthan from the Mundra project, citing non-compliance on payment, security related issues. The step followed several CGPL notices to the discoms required under the power purchase agreements, thereby effectively terminating its contract.

The three Rajasthan discoms accounted for 10 percent of the total capacity from Mundra UMPP.